1. Field of the Invention
The present invention relates to a level sensing safety device, more particularly a level sensing safety device, which is used on a drinking water dispenser for effecting cut-off of electricity when level of water in the dispenser is too low, and which can still function to effect cutting of electricity when the water dispenser is made to fall over to become virtually empty by unexpected external force.
2. Brief Description of the Prior Art
Level sensors are indispensable in drinking water dispensers that are equipped with heating devices to heat and boil water contained therein so that when water is running out, power to the heating devices can be automatically cut off to prevent the heating devices from over-heating or being burnt, avoiding danger and damage to the dispensers.
Referring to FIG. 7, a conventional level sensor includes a magnetic tube 21, and a float 22.
The magnetic tube 21 is formed with an annular trench 23 a upper end portion, and has a magnet switch 25, and conducting wires received therein. The conducting wires are connected to the magnet switch 25, and wires 26. The float 22 has a central through hole, and has a magnet ring 27 received therein and disposed around the central through hole.
In combination, the magnetic tube 21 is fixedly disposed on the bottom of the water container in an upright position. The float 22 is passed around the magnetic tube 21 at the central hole thereof, and a C-shaped engaging ring 24 is fitted onto the annular trench 23 of the magnetic tube 21 to prevent the float 22 from separating from the magnetic tube 21.
When level of water contained in the container of the dispenser is high enough to support the float 22 at the upper portion of the magnetic tube 21, the magnet ring 27 is close to the magnet switch 25 to make the same conductible so that electric current is allowed to travel through the same, thus allowing activation of a heating device (not shown) of the water dispenser. When water is running out, and the float 22 moves down to lower portion of the magnetic tube 21, the magnet ring 27 is farther away from the magnet switch 25 to become incapable of making the same conductible; thus, undesired activation of the beating device is prevented.
However, the level sensor is found to have a disadvantage that when the water dispenser is made to fall over by unexpected external force, and causes the water to flow out of the container, the float 2 move to the C-shaped ring 24, causing the magnet ring 27 to be close to the magnet switch 25 to make the same conductible. Consequently, the heating device is activated by mistake to cause danger when there is virtually no water in the dispenser container.
It is a main object of the present invention to provide a level sensing safety device to a drinking water dispenser that can effect cut-off of electricity when level of water in the dispenser is too low, and which can still function to effect cut-off of electricity when the water dispenser is made to fall over to become empty by unexpected force.
The present level sensing safety device for water dispenser includes a magnetic tube, and a float. The tube is disposed on the bottom of a water container of the dispenser. (A first, and a second magnet switches are disposed in the tube, and connected in series. The float is movably fitted around the tube, and has a magnet ring, which can be moved close to the first switch to make the first switch same become conductible if there is sufficient water in the container. A weight is movably fitted around the magnetic tube at a central through hole thereof. The weight has a magnet ring disposed around the central hole thereof, and has bigger density than water. The weighted ring is normally close to the second switch due to gravity to make the same become conductible. Thus, heating device of the dispenser can be activated when there is sufficient water. When the container are made to fall over, the weighted ring moves away from the corresponding switch to make the same become not-conductible to prevent the heating device from being activated.